Miscarriage is known to be one of the most common complications of pregnancy. The failure of pregnancy in the first trimester occurs in approximately 15-20% of pregnancies that have been documented by hCG testing, but the actual percentage of early pregnancy loss has not been precisely determined due to unconfirmed pregnancies [1]. RSA, is defined as the loss of three or more consecutive pregnancies, which is known to occur in 1-2% of couples attempting to conceive [2]. Medical causes of RSA usually are of immunological origin, in many cases associated with allogeneic immunity of the maternal immune system attacking paternal antigens, which is believed to account for 40-50% of miscarriages [3].
No method of treatment with definite curative effect is available heretofore. Currently, one widely used method for treating immunological RSA is lymphocyte immunotherapy. Immunotherapy of RSA has been applied both in China and other countries since Taylor and Faulk infused to a patient of unexplained RSA a suspension of mixed leukocytes derived from her spouse in 1981, which was subsequently confirmed in larger trials [4]. For this type of therapy, the immunogen is lymphocytes from the spouse in most cases. The immunotherapy includes isolating lymphocytes from the spouse's venous blood for intracutaneous injection. Alternatively, the condensed leucocytes or whole blood from the spouse can also be intravenously injected. Usually, the immunization is performed every 2 weeks for a total of 2 to 4 times before pregnancy and boosted 1 to 3 times after pregnancy. Twenty years after the application of lymphocyte immunotherapy for treating RSA, a great deal of studies from China and other countries have indicated that the therapeutic effect of this therapy is not definite and the therapy has some serious adverse side effects. Most literatures on immunotherapy of RSA from 1981 to 1994.9 had been reviewed. It was found that only one of the six studies that were worthy of analysis demonstrated the effectiveness of the immunotherapy. There was no statistically significant difference between the therapy group and the control group in the other studies. In addition, the lymphocyte immunotherapy has some serious adverse side effects such as erythrocyte sensitization, thrombocytopenia and intrauterine growth retardation of fetus etc. Some diseases transmitted by blood such as AIDS may be transferred from one individual to another due to the living cells with intact nuclear materials are used in lymphocyte therapy.